[Eeglablist] Importing and Exporting EGI Data To/From EEGLab

[Camilla Hileman]

Hi all,

I currently use NetStation (EGI) for data analysis. However, I would like
to use Independent Components Analysis on my data, and NetStation doesn't
have this option. So, I am trying to figure out how to import my data into
EEGLab. However, I'm having a difficult time with this. I have a few
questions, and I would be quite grateful to anyone who could help out!

1. When I input the data into EEGLab, I get the following warning/error
messages:

Warning: This function can only import continuous files or
         epoch files with only one length for data epochs
Only one segment, cannot read portion of the file
Importing binary EGI data file ...
eeg_checkset warning: 3rd dimension size of data (1) does not match the
number of epochs (0), corrected
eeg_checkset warning: number of columns in data (180829) does not match
the number of points (0): corrected
eeg_checkset note: upper time limit (xmax) adjusted so (xmax-xmin)*srate+1
= number of frames
pop_chanevent: importing events from data channel 139 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 138 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 137 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 136 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 135 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 134 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 133 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 132 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 131 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
pop_chanevent: importing events from data channel 130 ...
eeg_checkset note: creating the original event table (EEG.urevent)
Removing 1 channel(s)...
eeg_checkset note: re-creating the original event table (EEG.urevent)
Creating a new ALLEEG dataset 1

I'm having a difficult time interpreting these error messages,
particularly given that I am using a 128 channel (plus reference) cap. So,
I'm not sure why channels 130-139 are being mentioned in the error
message. When I look at the data in EEGLab, it SEEMS to look okay. Is
there an alternative way to export the data? Or is there a way to double
check to make sure that the data exported correctly? I've tried to export
a text file of the data from EEGLab, but the text file is SO big (129
columns x 181,000 rows) that it's difficult to read and won't fit into
Excel.

2. I am mainly exporting the data into EEGLab to use Independent
Components Analysis. After using this tool, I will need to perform several
other operations on my data. It appears that EEGLab can perform most of
these operations ... but perhaps not everything? I can't figure out how to
get EEGLab to segment the data based on the type of stimulus and whether
the participant responded to the stimulus correctly. Also, I can't figure
out how to get EEGLab to automatically detect and export latency/amplitude
information. Is anyone aware of how to do this in EEGLab? Alternatively,
if this can't be done in EEGLab, how can the data be exported back to
NetStation?

I would be very thankful to anyone who would have some advice!

Best,

Camilla Hileman
University of Miami